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1、生物专业英语大三生物科学创印工坊ENGLISHFORBIOLOGY STUDENTSLessonOneInsidetheLivingCell:StructureandFunctionofInternalCellParts1、Cytoplasm:TheDynamic,MobileFactory(细胞质:动力工厂)Mostofthepropertiesweassociatewithlifearepropertiesofthecytoplasm.Muchofthemassofacellconsistsoft
2、hissemifluidsubstance,whichisboundedontheoutsidebytheplasmamembrane.Organellesaresuspendedwithinit,supportedbythefilamentousnetworkofthecytoskeleton.Dissolvedinthecytoplasmicfluidarenutrients,ions,solubleproteins,andothermaterialsneededforcellfunctionin
3、g.生命的大部分特征表现在细胞质的特征上。细胞质大部分由半流体物质组成,并由细胞膜(原生质膜)包被。细胞器悬浮在其中,并由丝状的细胞骨架支撑。细胞质中溶解了大量的营养物质,离子,可溶蛋白以及维持细胞生理需求的其它物质。2、TheNucleus:InformationCentral(细胞核:信息中心)Theeukaryoticcellnucleusisthelargestorganelleandhousesthegeneticmaterial(DNA)onchromosomes.(Inprokaryot
4、esthehereditarymaterialisfoundinthenucleoid.)Thenucleusalsocontainsoneortwoorganellesthenucleoli-thatplayaroleincelldivision.Apore-perforatedsaccalledthenuclearenvelopeseparatesthenucleusanditscontentsfromthecytoplasm.Smallmoleculescanpassthroughthenucl
5、earenvelope,butlargermoleculessuchasmRNAandribosomesmustenterandexitviathepores.真核细胞的细胞核是最大的细胞器,细胞核对染色体组有保护作用(原核细胞的遗传物质存在于拟核中)。细胞核含有一或二个核仁,核仁促进细胞分裂。核膜贯穿许多小孔,小分子可以自由通过核膜,而象mRNA和核糖体等大分子必须通过核孔运输。41生物专业英语大三生物科学创印工坊3、Organelles:SpecializedWorkUnits(细胞器:特殊的功能
6、单位)Alleukaryoticcellscontainmostofthevariouskindsoforganelles,andeachorganelleperformsaspecializedfunctioninthecell.Organellesdescribedinthissectionincluderibosomes,theendoplasmicreticulum,theGolgicomplex,vacuoles,lysosomes,mitochondria,andtheplastidsof
7、plantcells.所有的真核细胞都含有多种细胞器,每个细胞器都有其特定功能。本节主要介绍核糖体,内质网,高尔基体系,液泡,溶酶体,线粒体和植物细胞中的质体。Thenumberofribosomeswithinacellmayrangefromafewhundredtomanythousands.Thisquantityreflectsthefactthat,ribosomesarethesitesatwhichaminoacidsareassembledintoproteinsforexporto
8、rforuseincellprocesses.Acompleteribosomeiscomposedofonelargerandonesmallersubunit.DuringproteinsynthesisthetwosubunitsmovealongastrandofmRNA,"reading"thegeneticsequencecodedinitandtranslatingthatsequenceintoprotein.Severalribosom